Field
Aspects of the present invention generally relate to technology for detecting amount of developer by detecting change in capacitance.
Description of the Related Art
Many electrophotographical image forming apparatuses have remaining toner quantity detection units for notifying the user in a case where developer (hereinafter, “toner”) has been consumed. One method of remaining toner quantity detection involves detecting toner quantity by detecting change in capacitance between multiple electrodes disposed within a developing container. The configuration of these electrodes generally follows an electrode plate detection method where an electrode plate is disposed with a predetermined interval as to a developer bearing member (another electrode), and detecting capacitance between the electrode plate and the developer bearing member.
There has also been proposed a method to make comparison with a comparison circuit to improve accuracy of remaining toner quantity detection, such as described in Japanese Patent Laid-Open No. 9-190067. There has also been proposed a method where a comparison circuit is provided, and further a stirring cycle is also taken into consideration, such as described in Japanese Patent Laid-Open No. 2007-264612. However, these devices to detect remaining quantity of toner are costly. Accordingly, there has been demand for further reduction of cost.